Interpretive Summary: Fusarium Head Blight (FHB) is major disease of wheat that reduces grain yield and renders grain unsuitable for consumption due to production of the deoxynivalenol toxin. Growing resistant cultivars is one of the most efficient approaches to reduce FHB damage in wheat. However, resistance is difficult to breed for since it is controlled by several genes and the environment places a large role in disease development. Genes for resistance have been genetically mapped in FHB resistant spring wheat cultivars from China that are not adapted to the southeastern United States. The use of DNA markers that tag these FHB resistance gene regions can complement and facilitate traditional wheat breeding programs. In this study, resistance genes from the Chinese wheat line Ning7840 were transferred to the soft red winter wheat cultivar McCormick using DNA markers. Lines that combined the Fhb1 resistance gene with another gene on chromosome 2D expressed the highest resistance and lowest deoxynivalenol content when evaluated in field and greenhouse studies. These results indicate that the combination of these two genes would be useful to improve FHB resistance in soft red winter wheat varieties in the mid-Atlantic region.

Technical Abstract:
Fusarium Head Blight (FHB), caused by Fusarium graminearum, of wheat (Triticum aestivum L.) is a disease that periodically strikes the mid-Atlantic region of the USA. Breeding for resistant wheat varieties is an effective method of disease control. The objective of this study was to evaluate the effects of exotic FHB resistance Quantitative Trait Loci (QTL), singly and in combination, on FHB resistance in soft red winter wheat (SRWW). Three FHB resistance QTL on chromosomes 3BS (Fhb1), 2D, and 5A were introgressed from non-adapted Chinese cultivar Ning7840 into the adapted SRWW cultivar McCormick. Eight Near-Isogenic Lines (NIL) were developed by marker-assisted backcrossing. The NIL that combined 3BS and 2DL expressed the highest resistance and lowest deoxynivalenol (DON) content in four environments that included three field and one greenhouse studies. These results indicate that the combination of just two QTL (3BS and 2DL) would be useful to breed for improved FHB resistance in soft red winter wheat in the mid-Atlantic region.